"The computers arrived at the port sealed in containers with numbers matching those on the shipping documents.

"US officials were in the process of co-ordinating delivery to Babil area schools when the computers were discovered to be missing."

'Immediate investigation'

The statement said that the US army commander in southern Iraq, Major General Vincent Brooks, has called for "an immediate investigation into the actions of the Umm Qasr official".

Corruption has been a major problem for Iraq since the 2003 US-led invasion.

Transparency International's 2009 corruption perceptions index ranked Iraq as one of the world's most corrupt nations - 176th out of 180 countries.

But Talib Bayesh, the port director, told The Associated Press news agency that the equipment had been sitting in the port for more than 90 days and that, according to the law, any items sitting in the port for more than three months without being claimed could be confiscated by the port and sold at public auction.

"Thus we sold the shipment by auction for only $45,000," he said.

Companies using Umm Qasr, near the southern oil hub of Basra, to import grain have complained of heavy bribes being demanded, poor service and high handling costs that make the port one of the most expensive in the world for shippers.